Quantify the performance cost of third-party scripts.
Third-party scripts cost more than their size suggests, because each new domain adds a full connection setup. Tag managers make it easy to accumulate scripts nobody owns or monitors. Third-party code is the most common cause of poor field performance, and it is often the easiest to remove because much of it is unused.
Third Party Script Impact
Impact = transfer time + execution time + per-domain connection overhead
Impact = transfer time + execution time + per-domain connection overhead Third-party scripts cost more than their size suggests, because each new domain adds a full connection setup. Tag managers make it easy to accumulate scripts nobody owns or monitors.
Third-party code is the most common cause of poor field performance, and it is often the easiest to remove because much of it is unused.
This calculator takes 5 inputs: Number of third-party scripts, Average script size, Average execution time per script, Connection speed, Additional domains contacted. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.